Ok guys, i'm facing a really strange problem with my 86 rx that i have never heard before. It's happen when i release the gaz and let the car returns to the idle. When the engine rpm comes down to about 1500 rpm, there is a strange sound that begins and it becomes louder and louder until it comes to 600 rpm. And then the sound stop and all my central control lights light up. The sound seems to become from the fuses box inside the car

After that, when i press gaz to get the engine at about 2400 rpm all the central control lights turn off. If i let the car returns to idle, the same problem come over and over again.

Anybody has an idea ??

Alex

Sorry for my bad english...

 

Ok guys i have just checked all the fuses and when i take off the meter fuse the problem stop. I guess it's normal cause the central control lights are not working without that fuse, but the sound stop too. So i guess it's in the failure is in this electrical circuit.

I noticed too that this meter fuse is supposed to be a 7.5 A and in my car it was a 15 A. Could this be a cause of my problem ?

What do you think ?

 

Central control lights???

If you mean the warning/idiot lights/clock panel, and all the warning lights are coming on, at idle or at return to idle then your alternator is failing or you have a cold solder joint in the CPU.

What is your voltage when the lights are coming on??? if it is below 13 volts, chances are your alt is bad and needs to be replaced.

The buzz would then be from the relay in the CPU that indicates charge failure from the alt. With insufficent voltage (or borderline voltage) it will buzz as it switches on.

 

central control lights = warning/idiot lights/clock panel

I think you got it... the voltage is always at 12 volts. Even if lights are on or off the voltage is 12 volts. Like you said my alternator has probably a problem, because normally it's indicated 14 volts.

And the buzz i'm talking about is not like when you hit redline...

 

yeah, it will sound like an angry bee in the drivers kick panel as the relay in the CPU switches on if the voltage in borderline

 

The 12 volts i see, is it the 12 volts of the battery or it's what the alternator produces ?

If it's the 12 volts of the battery i guess that my car will not start soon when the battery will be dead ??

Thanks a lot Icemark...

Alex

 

It is the 12 volts that is available.

Anything under 12.6 volts and the car is only running on only the charge of the battery. When the battery is dead, the car will no longer run.

 

Something i don't understand is that yesterday i drove like an hour with this problem and the car never stopped, but I didn't check for the voltage drop. And today i start the car like 10 times and it started pretty well. Normally when you start the car it should take a lot of the battery right ??

Is it normal ??

Thanks again Ice

Alex

 

If the car starts pretty quick, then no it doesn't take a lot of juice to start it.

The key is the warning lights, when they are on, you are running only on battery power. If they are all off, then the alt is working (granted from your description not working well- but working none the less).

 

Is there an easy way to know if it's the alternator or wiring that is the failure ?

Thanks

Alex

 

Icemark thank you very much man. I changed the alternator this morning and everything is fine now.

Alex